Caramelization, a good source of food color and antioxidant capacity, depends on pH and sugars. However, no thorough study regarding the interactive role of the color and antioxidant capacity in caramel could be found. In this paper, four sugars (including monosaccharide and disaccharide) with different concentrations (1–40%) at different pH (pH 3, 7 and 10) were heated at 90 °C for various durations (0–42 h). Results from 240 samples indicated that caramels from monosaccharide with higher concentration exhibited better antioxidant capacity at more alkaline condition. High sugar concentration (40%) may partially overcome the influence of low pH on monosaccharides or high pH on disaccharide. Browning intensity (A420) was found to be a good index in monitoring the antioxidant capacity of caramel. ΔpH may closely reflect the increase rate of antioxidant capacity, which has not been reported before. Further statistic analysis through principal component analysis (PCA) and structural equation model (SEM) revealed that browning pigment, the interactive result of sugar concentration and pH, instead of colorless intermediate, was the major contributor on classifying the caramels or exhibiting antioxidant capacity. This is the first paper regarding the representative role of A420 in caramel by confirmatory path analysis.